add custom hass integration for doorbell button

[max@…]

it uses a plain rf signal so we could use an sdr (we have one on the shibari pc) to catch it and use it to actually trigger the doorbell people use

[max@…]

​https://manuals.plus/avantek/cb-21-wireless-doorbell-kit-manual

[m]

we can't use the shibari PC sdr to trigger it -- it's recieve only. we'de need something more expensive / a lime-sdr or something

still, being able to recieve when the doorbell gets triggerred would be something and we can work up to a sending SDR too.

[max@…]

broadcasts at 443.93 mhz even though the manual says 433.92, seems to just be a burst, not encoded data or anything